The vast majority of aircraft land on solid—and often paved—surfaces, using three or more wheels (a 747-400, for example, has 18 wheels in four sets of four, with two additional wheels at the nose). The wheels are typically shod with tires of more-or-less conventional heavy-duty construction.
Aircraft landings place significant stresses on landing-gear tires: a plane may land at a speed of 80-150 mph (128-240 km/h), yet when the tires touch down, they are scarcely turning. Therefore, they must spin up from a standstill to match the landing speed very quickly, and until they do, they skid along the runway, burning off rubber tread, creating flat spots and occasionally destroying a tire. (Runways commonly have a black skid-marked segment at one end where most planes touch down, and photos of planes landing often show clouds of smoke from the skidding tires.)
A number of devices and systems have been proposed to reduce landing-related wear on tires by accelerating, spinning or pre-rotating the wheels of an aircraft in preparation for landing. However, none of these have achieved significant commercial success, possibly due to excessive mechanical complexity, weight and/or inadequate durability. A new design that helps pre-rotate aircraft tires for landing may offer longer tire life, improved landing safety, reduced parts fatigue and maintenance cost, and other benefits for aircraft owners and operators.